Much of the current scholarships on Islamic social movements in Muslim-majority countries focus on the political discourses of conservative/fundamentalist Islamic groups such as Al Qaeda and Hamas. Fewer scholarships have examined the role of theological ideas in influencing the political discourse of progressive/liberal leaning Islamic groups such as the Gulen Movement (GM) from Turkey and the Nahdlatul Ulama (NU) from Indonesia. Virtually none of the scholarships on these two movements have examined them from a comparative historical perspective. Utilizing constructivist international relations theory, this study attempts to make a theoretically informed cross-regional comparison between these two groups. It analyzes similar and different strategies utilize by these groups to promote and institutionalize progressive Islamic ideas - defined in this study as theological support toward democracy, state-religion separation, and religious tolerance/pluralism - within their respective societies. By conducting comparative historical, cross-regional study of these two Islamic movements, my project serves as a theory development exercise of the role of moral authority leadership and its role in disseminating new theological ideas beyond the artificial regional boundaries that has historically made scholarship on political Islam and Islamic social movements in the Middle East and Southeast Asia to exist largely separately, with little dialogue and collaboration with one another. This study brings together existing knowledge about Islamic social movements from the two countries in order to develop a new theory on the role of theological change within Islamic social movements that is generalizable across the Islamic world. The data of this research consist of historical documents, secondary studies, and in-depth interviews with officials and activists from these movements.